Conventional semiconductor memory devices may employ read-while-write operations. In a read-while-write operation, a read operation is performed to a bank or memory area, while a write operation is performed to another bank or memory area. In a conventional phase-change memory device in which banks are arranged vertically (e.g., in a stack structure), a read operation is performed to a bank in one layer, while a write operation is performed to bank in a different layer. Conventionally, during a read-while-write operation, a write voltage is applied to a global bit line and a read voltage is applied to another global bit line
Read-while-write operations may increase the integrity and/or speed of phase-change (or other) memory devices. But, when two global bit lines are positioned relatively close to one another, coupling noise may be generated due to the concurrent or simultaneous application of the write and read voltages, which are different from one another. The coupling noise may change a value of data stored in a memory cell thereby decreasing reliability of the semiconductor memory device.